These Gross Facts About Dust Mites Will Make You Want to Clean ASAP

O-M-G. Get a vacuum, stat.

Have you done your spring cleaning yet? Either way, grab a Hazmat suit and your best vacuum, because you’re definitely going to want to clean again once you learn a little more about the little creatures living rent-free in your homes.

Okay, to be fair, dust mites aren’t dangerous. You don’t need to fumigate your house or call poison control (and you definitely won’t need a Hazmat suit either). Still, there’s good reason to keep their population numbers low.

Here are the weird, kinda nasty facts you need to know about the dust mites you share your home with.

1. Dust mites look like microscopic spiders.

If you’re thinking to yourself, “I’ve never seen a dust mite in my home so I have nothing to worry about,” think again. Dust mites are teensy, tiny things: They only grow to about one-quarter to one-third of a millimeter, and you can’t see them with your eyes. Under a microscope, you’d see that dust mites look like white spiders. They have eight legs, so they’re arthropods (not insects).

2. Dust mites feed on dust (hence the name).

To be exact, they feed on the human skin cells found in dust. (They don’t care so much about the dirt, soot, and pollen that ends up in dust as well.) You shed about 1.5 grams of skin every day, according to the Asthma and Allergy Foundation of America (AAFA). That may not sound like much, but it’s enough to feed a million dust mites. Yes—you read that right. One. Million. Dust mites.

3. Dust mites live deep in your home’s upholstery.

The inner layers of your carpet, curtains, beds, and upholstered furniture are a dust mite’s dream. That tends to be where dust (um, your dead skin) collects. Don’t be ashamed: Dust mites exist in most homes and it’s nearly impossible to get rid of them completely. A study in The Journal of Allergy and Clinical Immunology found that around 80 percent of U.S. homes had detectable levels of dust mites in at least one bed.

4. Dust mites are not parasites, and they don’t bite you.

Dust mites have a pair of creepy, pincer-like claws near their mouth, so they look a little threatening under a microscope. But fear not: These little guys aren’t parasites like lice and bed bugs. They don’t feed on blood, and they don’t bite humans. (Check out these weird facts about lice.)

That doesn’t mean dust mites are harmless, though. The problem with dust mites is actually that they trigger allergic reactions for many people with allergies, asthma, and eczema. They create a harmful allergen from their body parts and—ummm—their poop. (Here are more common asthma triggers to be aware of.)

5. Dust mites love humidity.

Dust mites don’t drink water; they absorb it from the air, so they loooove humid climates. Specifically, they prefer temperatures between 68 and 77, and they like humidity between 70 and 80 percent, according to AAFA. They will die in low humidity levels, or in very cold or hot temps.

Your skin might be crawling at the thought of these microscopic pests, but dust mites are unavoidable. To avoid allergic reactions and keep their populations (and poop) on the low end, these tips may help, according to the National Institute of Environmental Health Sciences:

Use a dehumidifier if necessary to keep your relative humidity below 50 percent.